IV drip and electrical telegraph: what they have in common

1. Step 1. IV drip — has part — Catheter. A catheter.
2. Step 2. Catheter — is made of — Polyvinyl chloride (PVC). Plastic catheters.
3. Step 3. Polyvinyl chloride (PVC) — is material for — Vinyl record. Vinyl is PVC.
4. Step 4. Vinyl record — evolved from — Gramophone. A long-playing record.
5. Step 5. Gramophone — evolved from — Phonograph. A flat disc instead of a cylinder.
6. Step 6. Phonograph — was inspired by — Electrical telegraph. Edison came to the phonograph while working on recording telegraph and telephone signals.

Open Evothings